Apparatus and method for producing a non-woven fabric



Jan. 21; 1969 M. R. LIVINGSTON ETAL 3,422,510

APPARATUS AND METHOD FOR PRODUCING A NON-WOVEN FABRIC Filed Dec. 50,1964 Sheet 01*4 Jan. 21, 1969 M. R. LIVINGSTON ET AL 3,422,510

APPARATUS AND METHOD FOR PRODUCING A NON-WOVEN FABRIC Filed Dec. 30,'1964 Sheet 2 of 4 Jan. 21, 1969 M. R. LIVINGSTON ETAL 3,422,510

Jan. 21, 1969 M. R. uvmes'rou ET AL 3,422,510

APPARATUS AND METHOD FOR PRODUCING A NON-WOVEN FABRIC Filed Dec. 30.1964 Sheet 4 of 4 1 Claims Int. Cl. D02g 1/16; 1304i] 17/00; D03d 3/04ABSTRACT OF THE DISCLOSURE Apparatus and method for producing anon-woven fabric, said method comprising feeding at a low overfeed afirst sheet of warp yarns to the inlet slit of a bulking zone;simultaneously feeding to the inlet slit at an angle to the feed of thefirst sheet at least one other sheet of warp yarns at a higher feed ratethan the first, said sheets being in at least partially superimposedrelationship; oscillating the other sheet with respect to the firstsheet prior to entry into the inlet slit; bulking the combined warpyarns in the bulking zone with a fiuid medium under pressure wherebyadjacent yarns are entangled to form a nonwoven fabric; and withdrawingthe resulting fabric from the outlet slit of the bulking zone.

This invention relates broadly to apparatus and method for producing anon-woven fabric. The scope of the invention also includes the non-wovenfabric itself, which is unique in that it is made solely from warpyarns. In this new fabric, entangled Warp yarns and/or filaments thereofserve as a substitute for the normal filling.

In accordance with the present invention a plurality (e.g., 2, 3, 5, 7or any desired number) of sheets of warp yarns of any flexiblefilamentary material such as any of the available textile filaments, orblends or combinations thereof, are bulked to produce a continuous sheetof nonwoven fabric in any desired width. As a result, the inventionprovides a low-cost, high-speed technique for producing fabrics that aresimilar to those Which are knitted or woven from bulk or spun yarns.

It was known prior to the present invention that continuous filamentyarns could be bulked (see, for example, U.S. Patents 2,783,609;2,829,420; 2,852,906; and 2,884,- 756), which is also true of stapleyarns as illustrated by U.S. Patent 2,869,967. Filamentary or fibrousmat materials are likewise known, as exemplified by U.S. Patents2,736,676; 2,859,506; and 2,875,503. let devices for use in connectionwith the processing of filamentary materials are also known (see, forinstance, U.S. Patent 2,924,868 and the patents referred to therein;also, U.S. Patent 3,055,080).

To the best of our knowledge and belief, however, it was not known orsuggested prior to our invention to produce a bulked non-woven fabricfrom two or more warps of yarns as briefly described in the first twoparagraphs of this specification and more fully hereafter.

It is a primary object of the present invention to provide a new andimproved method of making a non-Woven bulky fabric that simulates aWoven or knitted fabric at a low cost and a high production speed.

Another object of the invention is to provide apparatus, including acomponent thereof (more particularly a slitjet device), by theutilization of which the method features of the invention can bepracticed.

Still another object of the invention is to provide a new non-wovenfabric, more particularly a non-woven bulky fabric, that contains nofilling (as do knitted and Woven fabrics), and which can be produced ata relatively low tates cost and high production speed, e.g., at from 25to 50 yards or more per minute, and in any desired width.

Other objects of the invention will be apparent to those skilled in theart from the following more detailed description and from theaccompanying drawing which is illustrative of a preferred embodiment ofthe invention.

The novel features of the invention are set forth in the appendedclaims. The invention itself, however, will be more readily understoodfrom the following description taken in connection with the accompanyingdrawing, which is illustrative of the invention, and wherein FIGURE 1 isan isometric, somewhat schematic, view illustrating the main processfeatures of the invention, and shows warps of yarn from which thenon-woven fabric is made; and also, guide or directional change rolls,feed rolls, means (specifically weaving reeds) for keeping the warpyarns in approximately parallel relationship, and a slit-jet device(with one end exposed for purpose of clarity) wherein the combinedsheets of approximately parallel warp yarns of continuous length areentangled (more particularly mechanically, or physically entangled), ashereafter more fully described, to form a bulky or bulked fabric, andwherein, also for purpose of clarity, the thickness of the fabricemerging from the slit-jet device has been exaggerated;

FIGURE 2 is an isometric view of the slit-jet device of FIGURE 1 withone end plate illustrated as being in an exploded position in order toshow more clearly the details of the device;

FIGURE 3 is a greatly enlarged view, partly isometric and partly plan,that illustrates in simple form the mode of entanglement that occursbetween individual, adjacent, warp yarns when only two sheets or warpsare used in the process; and

FIGURE 4 shows in flow-sheet form a modification of the processillustrated in FIGURE 1 by including two additional warps of yarn in thefeed to the slit-jet device and showing means for imparting additionaltransverse strength to the finished fabric as desired or as conditionsmay require.

The present invention provides a new, unobvious and economical method ofmaking a relatively inexpensive non-woven fabric. Briefly described, themethod comprises feeding at a relatively low overfeed a first sheet orcore warp of approximately parallel warp yarns to the inlet slit of theslit-jet device comprising a bulking zone having inlet and outlet slits.Simultaneously (i.e., along with the core sheet or warp) there is fed tothe inlet slit at least one other sheet or warp (e.g., 2, 3, 4, 5, 6, 7,8 or any desired higher number of sheets depending, for example, uponthe particular apparatus employed, the particular warp yarns used, andthe particular type or kind of non-woven fabric wanted) of approximatelyparallel warp yarns at a higher feed rate than that of the first sheet.

Some slight degree of overfeed of the core warp is necessary in order toprovide sufficient slackness to permit the filaments to open in theturbulent or bulking zone to which the core warp and other sheet(s) orwarp(s) subsequently pass. Otherwise, the loops formed in, or derivedfrom, filaments of yarns of the adacent other sheet(s), sometimes hereindesignated as etfect sheet(s) or warp(s), of higher overfeed than thecore warp cannot penetrate and become entangled in, or interlaced with,the core warp yarns and/or the filaments thereof. The overfeed of thecore warp may range, for example, from 0.5 to 10%, but preferably iswithin the range of from about 3% to about 8%. A core-warp overfeedsubstantially outside the aforementioned range of 0.5-10% generallyproduces a non- Woven fabric that is less suited for the usual textileapplications but may be suitable for other purposes.

The overfeed of the effect warp(s) ordinarily is at least in excess ofthe overfeed of the core warp. So far as is known there is no upperlimit on the overfeed of the effect warp(s) with respect to that of thecore warp other than the influence that the percentage overfeed has uponthe strength and weight of the finished fabric. A preferred range of theoverfeed of the effect warp(s) is from to 1000% in excess of theoverfeed of the core Warp, since within this range there can be producedfabrics having, in general, the widest appeal to the buyer.

The chosen overfeed of the efiect warp(s) is greatly dependent upon theparticular fabric construction employed and the characteristics desiredin the finished fabric. For example, a core warp of 2.00 denier yarn canbe bound together by a second warp of 100 denier fed at only 20%overfeed (i.e., 20% in excess of the feed rate of the core warp), andthe resulting fabric might be designated as having about 320.denier/end. Conversely, a 100 denier core warp can be bound together bya 30 denier second warp fed at 600% overfeed to give about 310denier/end. The fabrics have about the same weight, but theirappearance, hand and strength vary greatly.

The sheet or sheets being fed at a higher feed rate to the inlet slit ofthe bulking zone are oscillated with respect to the first sheet prior toentry into the aforesaid inlet slit, e.g., by means of an oscillatingweaving reed, or an oscillating comb such as those used on beamers orslashers. Other means of oscillating the effect sheet(s) of warp yarnsinclude heddles such as are used on looms; hooked needles that providecriss-cross oscillation (some needles moving left as others move right,etc.); air currents directed by movable vanes; and threaded rolls inwhich the threads, while being parallel, progress first in one directionand then either reverse or wander over the surface in random manner. Theoscillating means is advantageously one, such as an oscillating weavingreed or an oscillating comb, that also maintains the warp yarns inapproximately parallel relationship. A suitable device or devices, e.g.,one or more stationary weaving reeds or stationary combs, also isemployed to maintain the warp yarns of the first sheet approximatelyparallel to each other.

Other examples of oscillating means will be apparent to those skilled inthe art from the foregoing illustrative examples.

Ordinarily, in practicing the method features of this invention at leastone (or at least two) angularly-fed sheet of substantially parallel Warpyarns is fed from above and at least One (or at least two) angularly-fedsheet of substantially parallel warp yarns is fed from below the saidfirst sheet at a higher rate than the said first sheet.

The oscillation of certain of the feed sheets to which referencepreviously has been made may be carried out in various ways. Forexample, one angularly-feed sheet approaching the inlet slit of thebulking zone may be oscillated in phase but in reverse order with atleast one other angularly-feed sheet approaching the said slit; or, atleast one angularly-fed sheet approaching the inlet slit may beoscillated out of phase with at least one angularly-fed sheetapproaching the aforesaid inlet slit. Other variations in the movementsof the high overfeed elfect sheets have been suggested or indicated inan earlier paragraph describing various devices or means for effectingoscillation of said sheets.

The combined warp yarns are bulked in the bulking zone of a slit-jetdevice after entry therein through the aforesaid inlet-slit, moreparticularly in contact with a fluid medium, specifically a gaseousfluid medium, under pressure, e.g., high velocity air, nitrogen, argon,helium, carbon dioxide, flue gases, etc. In some cases, wet (saturated)or high-pressure (superheated) steam may be used. The only restrictionon the use of steam is that its temperature should not be so high as tocause the yarns in the warps being processed to melt or to fusetogether. Preferably air is used as the bulking medium.

By practicing the method of this invention including bulking in theaforementioned slit-jet device there is obtained a non-woven fabric,comprising sheet material consisting essentially (or consisting solely)of warp yarns, i.e., multifilamentary warp yarns, of continuous lengthwherein yarns of the warp that are in close proximity to each other areat least partly, if not almost or substantially completely, entangledtogether by loops formed in individual filaments of otherclose-proximity warp yarns. These loops are created during formation,and specifically during bulking, of the non-woven fabric.

As is illustrated more clearly in FIGURE 3, and in the production ofwhich will be described more fully hereafter with particular referenceto that figure, the invention provides a non-woven fabric comprisingsheet material consisting essentially of warp yarns of continuous lengthwherein adjacent yarns thereof are opened up and penetrated in at leastsome of the openings by loops in individual filaments of other adacentwarp yarns, whereby the said loops become entangled in, and moreparticularly interlaced with, the various adjacent warp yarns and holdthe said yarns together. It will be understood, of course, by thoseskilled in the art that a more specific embodiment of such a non-wovenfabric is a bulky non-woven fabric wherein at least some of theaforementioned adjacent warp yarns are those wherein the warp yarns arenext to each other.

As will be further noted from a consideration of FIG- URE 3 and thefollowing more detailed description, the invention also provides anon-woven fabric material wherein the filamentary component consistsessentially or solely of warp yarns of continuous length, and at leastsome (if not a major number or almost all or substantially all) of theindividual yarns of the warp are connected to warp yarns adjacentthereto by cross-overs in the form of loops derived from individualfilaments of warp yarns interposed between the said cross-overs. Apreferred fabric of the invention is a bulky non-woven fabric comprisedof organic filamentary material (examples of which will be given laterherein) consisting of warps of the same or different organic yarns incontinuous length and wherein adjacent yarns of the warp are at leastpartly (if not mostly or substantially completely) entangled together byloops derived from filaments of other adjacent warp yarns.

The invention also provides (see FIGURE 4 and the description hereaftergiven with reference to that figure) a bulky non-woven fabric comprising(1) sheet material consisting essentially or solely of warp yarns ofcontinuous length and wherein yarns of the warp that are in closeproximity to each other are at least partly entangled together by loopsin (or derived from) individual filaments of other close-proximityyarns; and (2) a bonding agent that further bonds or holds together thesaid warp yarns and thereby imparts additional transverse strength tothe said sheet material. It will be understood, of course, by thoseskilled in the art that a bonding agent may be used, if desired, inconjunction with any of the unbonded, non-woven fabrics of the inventionin order to increase the transverse strength of the fabric.

After the combined warp yarns have been bulked in the bulking zone ofthe slit-jet device to yield a non-woven fabric having theabove-described characteristics, the said fabric is withdrawn from theoutlet slit of the bulking zone, and either passed to further processingsteps (as illustrated in FIGURE 4, for example) or taken up on asuitable fabric take-up device.

The present invention also provides apparatus for producing a non-wovenfabric comprising:

A. a slit jet having inlet and outlet slits leading to a bulking zone;

B. means including guide rolls and driven feed rolls adapted for feedingat a low overfeed a first sheet of approximately parallel warp yarns tothe inlet slit of the said slit jet;

C. means including guide rolls and driven feed rolls adapted forfeeding, simultaneously with the said first sheet, to the inlet slit ofthe said slit jet at least one other sheet of approximately parallelwarp yarns at a higher rate than that of the said first sheet;

D. oscillating means adapted to oscillate the said other sheet or sheetswith respect to the first sheet prior to entry in the said inlet slit;

E. means for introducing a fluid bulking medium under pressure to thebulking zone of the said slit jet; and

F. means for withdrawing a non-woven fabric wherein adjacent yarns areintertwined with each other from the outlet slit of the said slit jet.

As previously indicated, the above-described apparatus advantageouslyaddition-ally includes stationary means, e.g., a stationary weaving reedor reeds, for maintaining in approximately parallel relationship thewarp yarns of which the aforesaid first or core sheet or warp isconstituted prior to entry thereof in the inlet slit of the slit jet.Advantageously, too, the oscillating means additionally includes means,e.g., an oscillating weaving reed or reeds, for maintaining inapproximately parallel relationship the warp yarns of which theangularly-fed sheet or sheets are constituted prior to entry thereof inthe inlet slit of the aforesaid slit jet.

Of particular importance as a component of the apparatus of thisinvention and for use in practicing the method features of the inventionto obtain a bulked, nonwoven fabric is the aforementioned slit-jetdevice. In a preferred embodiment of the invention this devicecomprises:

(A) an inverted channel having downwardly extending side walls;

(B) an angle-shaped quarter-inlet jet member removably attached to oneside wall and an angle-shaped quarteroutlet jet member removablyattached to the opposite side wall of the said inverted channel, thebases of the said jet members abutting the lower edges of the said sideWalls and extending inwardly to form a slotted bottom wall for the saidinverted channel, the vase of the said quarter-inlet jet member havingan outer surface and a machined plane inner surface that slopesdownwardly towards its inwardly-extending edge and the base of thequarter-outlet jet member having a plane inner surface and a machinedplane outer surface that slopes upwardly toward its inwardly-extendingedge, and the aforesaid jet members in their fixed operating positionsproviding means for entrance of a bulking fluid to a bulking zone, andthe elements of (A) and (B) together forming a first chamber adapted toreceive a bulking fluid;

(C) a channel having upwardly extending side walls;

(D) an angle-shaped quarter-inlet jet member removably attached to oneside wall and an angle-shaped quarteroutlet jet member removablyattached to the opposite side wall of the said channel, the bases of thesaid jet members abutting the upper edges of the said side walls andextending inwardly to form a slotted upper wall for the said channel,the base of the said quarter-inlet jet member having an outer surfaceand a machined plane inner surface that slopes upwardly toward itsinwardlyextending edge and the base of the quarter-outlet jet memberhaving a plane inner surface and a machined plane outer surface thatslopes downwardly toward its inwardly-extending edge, and the aforesaidjet members in their fixed operating positions providing means forentrance of a bulking fluid to a bulking zone, and the elements of (C)and (D) together forming a second chamber adapted to receive a bulkingfluid, said first and second chambers being spaced apart to provide aninlet slit adapted to receive sheet material consisting of warp yarnsand an outlet slit adapted for the withdrawal of a sheet of non-wovenfabric;

(E) removably attached end closure plates for closing the ends of theaforesaid first and second chambers and the end space between the twochambers; and

(F) means for introducing a bulking fluid into each of the aforesaidfirst and second chambers.

Preferably the means of (F), supra, are means for introducinghigh-velocity air into each end of the aforesaid first and secondchambers. Alternatively, the air may be introduced (although lesssatisfactorily) into the top and into the bottom of the aforesaid firstand second chambers. The point of supply of the fluid is not importantso long as suflicient fluid is delivered to each member to maintainconstant pressure from end to end of each.

Referring now to the accompanying drawing and, more particularly, toFIGURE 1 thereof, it is there shown by way of illustration that sheetsof warp yarns 10, 12 and 14 of any desired filamentary material(numerous examples of which are hereafter given) are fed over guide ordirectional change rolls 16, 18 and 20. The aforementioned warps arethen fed to pairs of driven feed rolls 22, 24 and 26 (drive not shown).Each pair of feed rolls is controlled by a variable speed drive so thatthe overfeed of the warps can be adjusted to meet the specificproperties required in the finished fabric. The path of the warps passesthrough means for maintaining the warps in approximately equally-spaced,parallel relationship with each other, e.g., weaving reeds 28, 30 and 32or other similar devices. Weaving reed 30 is of the stationary typewhile reeds 28 and 32 are of the oscillating type with respect to centeror core warp 12.

The sheets or warps 10, 12 and 14 are introduced into the yarn-inletside 34 of the slit-jet device 42. The physical make-up of the layers orsheets of yarn in these three warps is comparable to a sandwich. Warp 12is the middle layer while warp 10 is below and warp 14 above it. Abulking medium, e.g., compressed air, is introduced to the lower (orsecond) air chamber 43 and the upper (or first) air chamber 44 of theslit-jet device 42 through conduits 50 and 62, respectively, which passthrough openings in end-closure plates 54 and 56, respectively (FIGURE2).

The bulking fluid, specifically air, from the air chambers 43 and 44passes through slit-jet passages 36 and 38, and encounters the threewarps in the bulking zone 40. In this zone, core sheet or warp 12 isbulked by filamentary and yarn entanglement, as briefly described aboveand more fully hereafter, with yarn from warps 10 and 14 and,specifically by loops in the individual filaments thereof. Warp 12 isused as the skeletal or sheet upon which all the bulking is done.

A major factor in obtaining the aforementioned results is the adjustmentof the overfeed rates of the other two warps, viz., 10 and 14, by meansof feed rolls 22 and 26. Warp or sheet 12 is fed at a relatively lowoverfeed rate while warps 10 and 14 are fed at considerably higheroverfeed rates, thereby causing the warps 10 and 14 to be bulked overwarp 12. Details of the overfeed rates of the core and other warps and adiscussion thereof have been given hereinhefore.

With regard to the degree of twist in the yarn, it may be mentioned thattwists up to about 5 t.p.i. in the low overfeed or core warp 12 andtwists up to the point of considerable liveliness (e.g., from 10 to 20t.p.i.) in the high overfeed warps 10 and 14 can be used. However, ifyarns twisted above about 1 t.p.i. in low overfeed warp 12 and aboveabout 0.5 t.p.i. in high overfeed warps 10 and 14 are used,cross-entanglement is restricted due to limited movement of thefilaments in the turbulent zone, as a consequence of which the resultingnon-woven fabric has a low transverse strength and poor cover. Hence, itis desirable and advantageous that yarns in the low overfeed or corewarp have a twist not exceeding about 1 t.p.i. and the yarns in the highoverfeed warps 10 and 14 have zero or very low twist (preferably notexceeding about 0.5 t.p.i.) in order to obtain the best results.

The bulked or finished non-woven fabric 48 leaves the bulking zone 40through the outlet slit 46, which also serves as the outlet for the airfrom the slit-jet device 42. The bulked or finished non-woven fabric,upon being withdrawn from the slit-jet device 42 by suitable drivenrollers (not shown) can then be taken up over rollers or otherwisehandled in any manner that is well known in the textile art.

Referring now more particularly to FIGURE 2, the slitjet device 42 thereshown may be made, for example, entirely (or at least the importantfunctional elements thereof) of stainless steel or of chromiumornickel-plated steel. It comprises an inverted channel 62 havingremovably attached lengthwise to the side walls thereof by means ofmachine screws 76 the angle-shaped quarterinlet jet member 66 and theangle-shaped quarter-outlet jet member 68. The base of the quarter-inletjet member 66 has an outer surface '79 and a machined plane innersurface 78 that slopes downwardly toward its inwardly extending edgewhile the base of the quarter-outlet jet member 68 has a plane innersurface 79a and a machined plane outer surface 82 that slopes upwardlytoward its inwardly-extending edge. The angles of both of theaboveindicated slopes are, for example, about to about 25 from thehorizontal, more particularly about The two quarter jet members 66 and68, in their fixed operating positions, form the air passage 38 to thebulking zone 40. In other words, the bases of the said jet members abutthe lower edges of the side walls of the inverted channel 62 and extendinwardly to form a slotted bottom wall for the said channel.

The other half of the slit-jet device comprises a channel 64 havingremovably attached lengthwise to the side walls thereof by means ofmachine screws 76 the angle-shaped quarter-inlet jet member 70 and theangle-shaped quarteroutlet jet member 72. The base of the quarter-inletjet member 70 has an outer surface 81 and a machined plane inner surface80 that slopes upwardly toward its inwardly-extending edge and the baseof the quarter-outlet jet member having a plane inner surface 83 and amachined plane outer surface 84 that slopes downwardly toward itsinwardly-extending edge. The angles of both of these above-indicatedslopes are, for example, about 15 to about more particularly about 20,and correspond to the angles of slopes mentioned in the precedingparagraph with reference to quarter-inlet and -outlet jet members 66 and68, respectively. The two quarter jet members 70 and 72, in their fixedoperating positions, form the air passage 36 to the bulking zone 40. Inother words, the bases of the said jet members abut the upper edges ofthe side walls of the channel 64 and extend inwardly to form a top wallfor the said channel.

The dimensions of the air passages 36 and 38 are critical, but aredependent primarily upon the deniers and degree of overfeed of the warpyarns being processed. Therefore, the spacings between the surfaces 78and 82 of the upper section and between surfaces 80 and 84 of lowersection must be adjustable. The required degree of adjustment can beprovided by using elongated holes 67 in member 66 through which pass thescrews 76. Due to the wide variations that are possible in warp yarnsand overfeed rates, no rules can be established concerning thedimensions of passages 36 and 38. However, they may vary from less than0.005 inch, perhaps 0.004 or even as little as 0.0035 inch, for fine orextremely fine denier warps with low overfeeds up to 0.050 inch andmore, perhaps 0.060 or even as much as 0.070 inch for heavy or veryheavy denier warps and high overfeed rates. Each fabric constructionrequires optimizing the slits at the beginning of the run.

The volume of bulking fluid, e.g., compressed air or other gaseous fiuidmedium, used by the jet depends mainly upon the dimensions of thepassages 36 and 38 and the pressure used. It may vary, for example, fromabout 25 cu. ft./in. of jet at p.s.i.g. to about 100 cu. ft./in. at 70p.s.i.g. with wider jet openings.

Yarn-inlet passage 34 and fabric-outlet passage 46 are formed byattaching end-cover plates 54 and 56 to the end of the above-describedhalf-jet assemblies, which also may be described as being first andsecond chambers. The aforesaid end cover plates are screwed to the saidfirst and second chambers by means of machine screws 60 passing throughslotted holes 58 into the tapped holes 74. The slotted holes 58 providemeans for adjusting the height of the yarn-inlet passage 34 and fabricoutlet passage 46. The height of the passages 34 and 46 should besufficient to accommodate, without friction, the sheets of warps used;and, also, should be sufficient to prevent a back-flow of the bulkingmedium, e.g., air.

If ridges 79b and 81a are used on the entering edges of outer surfaces79 and 81, respectively (see FIGURE 2), to make the slit jetself-threading, the spacing between the ridges may vary, for example,from 0.01 to 0.05 inch. If these ridges are so formed that they extend,for instance, about 0.03 inch above the surfaces 79 and 81, the spacingbetween the flat portions of these surfaces may then vary, for example,from about 0.07 to about 0.11 inch. The ridges 79b and 81a are made, ofcourse, by suitably machining the frontal or outward-extending edges ofouter surfaces 79 and 81, respectively.

Space 46, the exit port, may vary at its narrowest portion from, forinstance, 0.05 inch to 0.10 inch. The slope of the walls of the exitport may range, for example, from 5 to 10, the preferred angle beingabout 5. Difficulty is encountered in maintaining turbulence in thebulking zone if this slope is substantially more than 10.

End-cover plates 54 and 56 are provided with two conduits 50 and 52which are screwed into drilled and tapped holes 50a and 52a. A bulkingmedium, more particularly a fiuid medium and specifically a gaseousmedium (co-mmonly air), is piped under pressure to both ends of the jet42 in order to maintain equilibrium of air pressure in both lower airchamber 43 and upper air chamber 44. In this way an even flow of gaseousbulking medium, e.g., air, is assured across the entire face of theslit-jet device through passages 36 and 38. Any gaseous bulking mediathat have no deleterious effect upon the particular filaments may beemployed, numerous examples of which have been mentioned hereinbefore.

The use of liquid bulking media, e.g., water, is not preeluded but noadvantages ap ear to reside in the use of such media. Furthermore, thereare known disadvantages. For example, the volume and flow rates requiredwould necessitate the use of very large and costly pumping equipment,while the removal of liquid from the finished fabric would require theexpenditure of large quantities of heat.

Instead of having the bulking medium enter the chambers 43 and 44through the ends of said chambers, it may be introduced int-o each ofsaid chambers through one, two or more conduits entering the top, andthe same number entering the bottom of each of said chambers. To furnishthe required quantities of air, in some cases it may be necessary to usevery large headers connected to chambers 43 and 44 at closely spacedintervals. Air or other gaseous fluid mediu m should be available atpressures ranging, for instance, from 20 p.s.i.g. to p.s.i.g. Thepressure and flow rates must be adjustable be cause no prediction of theoptimum value of each for any given fabric construction can be made.

FIGURE 3 illustrates the bulking pattern that is produced rwhenpracticing the present invention. A pattern (or artificial weave orknit) results from the present invention that is believed to have beenunknown heretobefore in the art of bulking fabrics.

In FIGURE 3, A, B, C and D represent individual yarns from the lowoverfeed or core warp 12. As previously mentioned, twist in thesecore-warp yarns should not exceed about 1 t.p.i. for best operation.Yarns from warp 10 are designated 86 and 88, and only one filament fromeach of these is shown tracing its way through a portion of the fabric.As also has been mentioned previously, the yarns in the high overfeedwarp 10 should have zero or very low twist, preferably not exceeding 0.5t.p.i. for best results.

Filament Q from yarn 86, under the influence of the turbulent bulkingmedium, is whipped about rapidly with the result that many loops areformed therein. The yarns A, B, C and D are also whipped about by theturbulence, but movement of the individual filaments is restricted bythe low overfeed to a simple opening up of the yarn structure. Thispermits some of the loops formed in Q and its fellow filaments from yarn86 to penetrate the yarns A and B which are in close proximity. Theseloops become entangled into yarns A and B and serve to bind themtogether.

For the purpose of clarity and simplicity only the movement of filamentQ is shown, but each of the filaments of yarn 86 follows a path similarto that shown for Q. The result is that a multitude of cross-overfilaments binds yarns A and B together simply by being entangled thereinat intervals.

Filaments of yarn 88 undergo entanglement between yarns B and C, similarto that just described with refer ence to filaments of yarn 86,following paths in the manner illustrated by way of example for filamentR of yarn 88.

The oscillation of warp causes yarn 86 to move into the space betweenyarns B and C as at X-X, so that filament Q and its fellow filaments areinterlaced between B and C. This movement of whole yarns adds transversestrength to the fabric. At the same time, yarn 88 moves into the spacebetween C and D as shown by the path of filament R, and another yarn(not shown) moves into the space between A and B, the filaments theninterlacing these two yarns as illustrated by the path of filament S.

From the foregoing description it will be readily seen that if each yarn86, 88 is composed of, for example, 40 filaments, the interlacingbetween the yarns A, B, C and D of core warp 12 will become quiteintense, resulting in a strong structure with good cover. The use ofadditional high overfeed warps further strengthens the total structure,and many loops protrude from the surface to give a soft, spun-yarn typeof hand.

FIGURE 4 illustrates an embodiment of the invention wherein twoadditional sheets or warps of yarns 122 and 124 have been added withtheir corresponding directional change rolls 126 and 128. Driven feedrolls 130 and 132 plus the oscillating weaving reeds 134 and 136 make upthe forward half of this embodiment of the invention.

After passage of the five warps of yarns 122, 14, 12, 10 and 124 throughthe slit-jet device 42, a very bulky, non-woven fabric 120 emerges.Suitable means are provided to give the non-woven fabric 120 additionaltransverse strength if needed or desired. To this end bonding and/ orplasticizing agents may be fed through conduit 138 into spray nozzle 140where the spray 142 of bonding and/or plasticizing agents is directedonto and into the non-woven fabric 120. Any drippings are caught in thecatch tray 144.

Illustrative examples of bonding and/or plasticizing agents that may beused as described hereinbefore are solutions or dispersions in organicsolvents or water, i.e., latices of binders such as natural or syntheticrubber, polyvinyl acetate, copolyrners of vinyl acetate and vinylchloride, phenol-, urea-, melamine-aldehyde (specifically -formaldehyde)resins separately or in various combinations or modifications; acrylicresins; epoxy resins; insolubilized starches; and the like. The chosenbinder depends to a large extent upon the particular use of the endproduct.

Various plasticizers and other effect agents may be applied to thefabric, the chosen plasticizer depending, for example, upon suchinfluencing factors as the chemical constitution of the filamentarymaterial and the particular use of the finished fabric.

Examples of plasticizers that may be used are diethyl and dibutylphthalates, diethyl, dibutyl and diamyl tartrates, ethyl citrate, benzylalcohol, benzyl benzoate, di- (methoxyethyl) phthalate, the methyl andethyl ethers of ethylene glycol, monoethyl-p-toluenesulfonamide,monomethylxylenesulfonamide, triacetin, formic acid, acetic acid,trichloroethyl phosphate, triphenyl phosphate, triethyl phosphate,glyceryl diacetate, glyceryl triacetate, diacetone alcohol, ethoxyethylacetate, methoxyethyl acetate, butoxyethyl acetate, butoxyethanol,butoxyethoxyethanol, ethyl lactate, acetyl triethyl citrate, ethylenechlorhydrin, butyrolactone, triethanolamine, etc.

Referring again to FIGURE 4, the non-woven fabric is shown as beingpulled along by a driven wind-up mandrel (drive not shown), and thespray-treated fabric is passed into a curing or drying oven 146depending upon the type of agent or agents that have been sprayed orotherwise applied to the fabric 120. Upon leaving the oven 146, thefinished fabric is wound into rolls 148 on the wind-up mandrel 150.

Although the latter portion of this embodiment of the invention has beendescribed with particular reference to a non-woven fabric made from fivesheets of warp yarns, the same technique for applying bonding and/orplasticizing agents may be used, of course, in treating non-wovenfabrics made from three sheets of warp yarns as illustrated in FIGURE 1,or from a plurality of any other number of such sheets.

The filamentary materials of which the warp yarns used in practicingthis invention are comprised or composed may be of inorganic origin,e.g., glass filaments, or of organic origin, but preferably are organic.Examples of the latter are thermoplastic filaments such as nylon,polyesters such as polyethylene, terephthalate, polyurethanes,polycarbonates, acrylonitrile polymers and copolymers, polyester amides,polyethylenes, polypropylenes, ethers of cellulose, organic esters ofcellulose and the like. Thus the filaments may be lower alkanoic estersof cellulose such as cellulose propionate, cellulose butyrate, celluloseacetatebutyrate, and the like, and especially cellulose acetate. Thecellulose acetate may be conventional cellulose acetate having an acetylvalue of about 55% by weight (calculated as acetic acid) or it may becellulose triaceate having an acetyl value in excess of about 59%. Otherand more specific examples of organic filamentary material are thosecomprised of fiuorinated ethylene polymers and copolyrners such aspoly(monochlorotrifiuoroethylene), polyhexamethylene adipamide,polycaproamide, and the like.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A method of producing a non-woven fabric which comprises feeding at alow overfeed a first sheet of approximately parallel warp yarns to theinlet slit of a bulking zone having inlet and outlet slits;simultaneously feeding to the inlet of the said slit at an angle to thefeed of said first sheet at least one other sheet of approximate 1yparallel warp yarns at a higher feed rate than that of the said firstsheet, said sheets being in at least partially superimposedrelationship; oscillating the said other sheet or sheets with respect tothe said first sheet just prior to entry into the said inlet slit;bulking the combined warp yarns in the said bulking zone by contactingsaid yarns with a fluid medium under pressure whereby adjacent yarns areentangled with each other thereby to form a non-woven fabric; andwithdrawing the resulting nonwoven fabric from the outlet slit of thesaid bulking zone.

2. A method as in claim 1 wherein the first sheet is fed to the inletslit of the bulking zone at an overfeed not exceeding about 10%.

3. A method of producing a non-woven fabric which comprises feeding, atfrom about 2% to about 10% overfeed, a first sheet of approximatelyparallel warp yarns to the inlet slit of a bulking zone having inlet andoutlet slits; simultaneously feeding to the said inlet slit, at an angleto the feed of the first sheet, at least two other sheets ofapproximately parallel warp yarns at a higher feed rate than that of thesaid first sheet, said sheets being in at least partially superimposedrelationship; oscillating the said other sheets with respect to the saidfirst sheet just prior to entry into the said inlet slit; bulking thecombined warp yarns in the said bulking zone in contact with a fluidmedium under pressure whereby adjacent yarns are intertwined with eachother to form a non-Woven fabric; and withdrawing the resulting nonwovenfabric through the outlet slit of the said bulking zone.

4. A method as in claim 3 wherein the fluid medium with which the warpyarns are contacted in the bulking zone is a gaseous fluid medium underpressure.

5. A method as in claim 4 wherein the gaseous fluid medium underpressure is air under pressure.

6. A method as in claim 3 wherein at least one angularly-fed sheet ofsubstantially parallel Warp yarns is fed from below the said first sheetat a higher rate than the said first sheet.

7. A method as in claim 6 wherein at least one angularly-fed sheetapproaching the inlet slit of the bulking zone is oscillated in phasebut in reverse order with at least one other angularly-fed sheetapproaching the said slit.

8. A method as in claim 6 wherein at least one angularly-fed sheetapproaching the inlet slit is oscillated out of phase with at least oneangularly-fed sheet approaching the said slit.

9. A method as in claim 3 wherein at least two angularly-fed sheets ofsubstantially parallel warp yarns are fed from above and at least twoother angularly-fed sheets of substantially parallel warp yarns are fedfrom below the first said sheet at a higher rate than the said firstsheet.

10. Apparatus for producing a non-woven fabric comprising:

A. a slit jet having inlet and outlet slits leading to a bulking zone;

B. means including guide rolls and driven feed rolls adapted for feedingat a low overfeed a first sheet of approximately parallel warp yarns tothe inlet slit of the said slit jet;

C. means including guide rolls and driven feed rolls adapted forfeeding, simultaneously with the said first sheet, to the inlet slit ofthe said slit jet at least one other sheet of approximately parallelwarp yarns at a higher rate than that of the said first sheet;

D. said means of B and C including means feeding said sheets to saidslit jets in angular at least partially superimposed relationship;

E. oscillating means adapted to oscillate the said other sheets orsheets with respect to the first sheet just prior to entry in the saidinlet slit;

F. means for introducing a fluid bulking medium under pressure to thebulking zone of the said slit jet; and

G. means for withdrawing a non-woven fabric wherein adjacent yarns areentangled with each other from the outlet slit of the said slit jet.

11. Apparatus as in claim 10 which additionally includes stationarymeans for maintaining in approximately parallel relationship the warpyarns of which the said first sheet is constituted prior to entrythereof in the inlet slit of the said slit jet.

12. Apparatus as in claim 10 wherein the oscillating means additionallyincludes means for maintaining in approximately parallel relationshipthe warp yarns of which the said other sheet or sheets are constitutedprior to entry thereof in the inlet slit of the said slit jet.

13. Apparatus as in claim 12 wherein the oscillating means is at leastone oscillating Weaving reed through which pass the warp yarns of whichthe said other sheet or sheets are constituted prior to entry thereof inthe inlet slit of the said slit jet.

14. A slit-jet device adapted for use in producing a bulked non-wovenfabric, said device comprising:

A. an inverted channel having downwardly extending side walls;

B. an angle-shaped quarter-inlet jet member removably attached to oneside wall and an angle-shaped quarteroutlet jet member removablyattached to the opposite side wall of the said inverted channel, thebases of the said jet members abutting the lower edges of the said sidewalls and extending inwardly to form a slotted bottom wall for the saidinverted channel, the base of the said quarter-inlet jet member havingan outer surface and a machined plane inner surface that slopesdownwardly towards its inwardly-extending edge and the base of thequarter-outlet jet member having a plane inner surface and a mechanicalplane outer surface that slopes upwardly toward its inwardly-extendingedge, and the aforesaid jet members in their fixed operating positionsproviding means for entrance of a bulking fluid to a bulking zone, and

the elements of A and B together forming a first chamber adapted toreceive a bulking fluid;

C. a channel having upwardly extending side walls;

D. an angle-shaped quarter-inlet jet member removably attached to oneside wall and an angle-shaped quarteroutlet jet member removablyattached to the opposite side wall of the said channel, the bases of thesaid jet members abutting the upper edges of the said side walls andextending inwardly to form a slotted upper wall for the said channel,the base of the said quarter-inlet jet member having an outer surfaceand a machined plane inner surface that slopes upwardly toward itsinwardly-extending edge, and the aforesaid jet members in their fixedoperating positions providing means for entrance of a bulking fluid to abulking zone, and

the elements of C and D together forming a second chamber adapted toreceive a bulking fluid, said first and second chambers being spacedapart to provide an inlet slit adapted to receive sheet materialconsisting .11 1 warp yarns and an outlet slit adapted for thewithdrawal of a sheet of non- Woven fabric;

E. removably attached end closure plates for closing the ends of theaforesaid first and second chambers and the end space between the twochambers; and

F. means for introducing a bulking fluid into each of the aforesaidfirst and second chambers.

15. A slit-jet device as in claim 14 wherein the means of F are meansfor introducing high-velocity air into each end of the aforesaid firstand second chambers.

References Cited UNITED STATES PATENTS 3,055,080 9/1962 Claussen et al.5734 X 3,110,151 11/1963 Bunting et al 2872 X 3,117,056 1/1964 Katz etal 161-170 ROBERT F. BURNETT, Primary Examiner.

R. L. MAY, Assistant Examiner.

US. Cl. X.R.

